The use of obsolete Contax / Yashica lenses on Canon EOS bodies is relatively common, but some exotic combinations of lenses and bodies are little documented and their compatibility unknown. I have now had some experience adapting two C/Y lenses on two Canon EOS bodies and I can report the results, unfortunately not enthusiastically.
| Camera | Lens | Result: mirror | Result: meter |
| EOS 5 | Carl Zeiss Tessar 45/2.8 | hits the lens | off about 1-1.5 EV |
| EOS 5 | Carl Zeiss Sonnar 135/2.8 | hits the lens | off about 1-1.5 EV |
| EOS 1n | Carl Zeiss Tessar 45/2.8 | hits the lens | OK |
| EOS 1n | Carl Zeiss Sonnar 135/2.8 | clear | OK |
By the way, the EOS 5 has the undeniable advantage of a very silent operation over EOS 1n but, besides this, the 1n is clearly a better camera.